Dissertations / Theses on the topic 'Branching factor'

Thesis (Ph.D. in Molecular Biology) -- University of Colorado Denver, 2007.
Typescript. Includes bibliographical references (leaves 160-175). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Neuroscience
Ph.D.
The formation of axon collateral branches from the pre-existing shafts of axons is an important aspect of neurodevelopment and the response of the nervous system to injury. Both the actin filament and microtubule components of the cytoskeleton are required for the formation of axon branches. Recent work has begun to shed light on how these two elements of the cytoskeleton are integrated by proteins that functionally or physically link the cytoskeleton. While a number of signaling pathways have been determined as having a role in the formation of axon branches, the complexity of the downstream mechanisms and links to specific signaling pathways remain to be fully determined. Neurotrophins are growth factors that have a multitude of roles in the nervous system. In sensory neurons nerve growth factor (NGF) induces branching through activation of phosphoinositide 3-kinase (PI3K). Recently, mitochondria have emerged as major determinants of the sites of axon branching. In this work we reveal a new role of neurotrophins in mitochondria fission. We report that NGF promote a rapid burst of mitochondria fission, followed by a new steady state of mitochondria length and density. Mek- Erk and PI3k pathways are required for NGF-induced fission. Mek-Erk controls fission through Drp1 activation, while we suggest that PI3K may contributes to the actin dependent aspect of fission. Drp1 mediated fission is required for NGF- induced branching in sensory neurons in vitro and the branching of sensory axons along the developing spinal cord. We reveal that fission is also required for the intra-axonal translation of the actin regulatory proteins Cortactin and Arp2 subunit from the Arp2/3 complex, an important aspect of NGF induced branching. Collectively, these observations reveal a novel role of neurotrophins in mitochondria fission and the formation of collateral branching
Temple University--Theses

Data from the 1998 run of the fixed target experiment NA48, located in the high intensity region of CERN's North Area, has been used to measure the branching ratio of K_L → μ⁺ μ^- γ. In addition to this, form factor parameters for a vector meson dominance models proposed by Bergstrom et. al. (BMS), D'Ambrosio et. al (API) and that of Chiral Perturbation Theory (χPT) have been measured for this mode. A total of 1150 μμγ candidates was observed with an estimated background of 13.2±6.2 events. The branching ratio BR(K_L → μ⁺ μ^- γ) was measured to be (4.00±0.12±0.7±0.7)x 10^-7 where the first error is statistical, the second is systematic and the third error comes from the uncertainty in the knowledge of the branching ratio of normalization mode, K_L → π⁺ π^-. The BMS model form factor parameter, α_K*, is measured to be -0.20±0.05. The χPT form factor parameters, α_MK and α_1.0 are measured to be 0.90±0.08 and 3.55±0.30 respectively. The measured value of the API model form factor parameter is α_API = -1.71±0.16. From this one can calculate a lower bound of -0.39 (90% CL) on the Wolfenstein CKM matrix parameter ρ.

It is well known that the branching factor of a computer based board game has an effect on how long a searching AI algorithm takes to search through the game tree of the game. Something that is not as known is that the branching factor may have an additional effect for certain types of AI algorithms. The aim of this work is to evaluate if the win rate of an evolutionary AI algorithm is affected by the branching factor of the board game it is applied to. To do that, an experiment is performed where an evolutionary algorithm known as “Genetic Minimax” is evaluated for the two low branching factor board games Othello and Gomoku (Gomoku is also known as 5 in a row). The performance here is defined as how many times the algorithm manages to win against another algorithm. The results from this experiment showed both some promising data, and some data which could not be as easily interpreted. For the game Othello the hypothesis about this particular evolutionary algorithm appears to be valid, while for the game Gomoku the results were somewhat inconclusive. For the game Othello the performance of the genetic minimax algorithm was comparable to the alpha-beta algorithm it played against up to and including depth 4 in the game tree. After that however, the performance started to decline more and more the deeper the algorithms searched. The branching factor of the game may be an indirect cause of this behaviour, due to the fact that as the depth increases, the search space increases proportionally to the branching factor. This increase in the search space due to the increased depth, in combination with the settings used by the genetic minimax algorithm, may have been the cause of the performance decline after that point.

Ein Algorithmus zur Identifizierung von Elektronen mit dem BABAR Detektor wird entwickelt. Basierend auf Spuren, deren Teilchenidentität aus rein kinematischen Überlegungen gefolgert werden kann, wird für Impulse zwischen 0.5 und 2.5 GeV/c die Selektionseffizienz für Elektronen zu 90% bestimmt. Im gleichen Impulsbereich liegt die Wahrscheinlichkeit, Pionen als Elektronen zu identifizieren, zwischen 0.05% und 0.1%. Auf diesem Algorithmus basiert die Messung des inklusiven Elektronen Impulsspektrums aus B-Meson Zerfällen anhand der Daten, die mit dem BABAR Detector am asymmetrischen Speicherring PEP-II ("B-Factory") aufgezeichnet wurden. Das Volumen der analysierten Daten entspricht einer integrierten Luminosität von 4.13 1/fb auf der Y(4S) Resonanz und 0.97 1/fb bei einer um 40 MeV verringerten Schwerpunktsenergie. B - Anti-B Ereignisse werden anhand hochenergetischer Elektronen identifiziert. Elektronen von einem semileptonischen Zerfall des zweiten B-Mesons werden durch die relative Ladung und Impulsrichtung zum hochenergetischen Elektron vom Untergrund aus semileptonischen Charm Zerfällen isoliert. Das inklusive Verzweigungsverhältnis für den semileptonischen Zerfall des B-Mesons wird zu (10.85 +-0.22(stat.) +-0.34(sys))% gemessen. Zusammen mit der Lebenszeit von B-Mesonen lässt sich daraus |V_cb| bestimmen: |V_{cb}| = 0.0406 +-0.0009(exp) +-0.0019(theory)
An algorithm for identification of electrons with the BABAR detector is developed. Based on pure samples of electrons and hadrons obtained from data, we determine the electron identification efficiency to be above 90% for momenta above 0.5 GeV/c in the laboratory frame, while the pion fake rate lies between 0.05% and 0.1%. Based on this algorithm, a measurement of the inclusive lepton momentum spectrum in B meson decays is performed. We analyze 4.13 fb^-1 and 0.97 fb^-1 of data recorded at and slightly below the Upsilon(4S) resonance with the BABAR detector at the PEP-II a symmetric B-Factory. B-Bbar events are tagged by a high momentum electron. Using charge and angular correlations, leptons from a second semileptonic $B$ decay are separated from secondary charm semileptonic decays. The inclusive branching ratio is measured to be (10.85 +-0.22(stat.) +-0.34(sys))% . Combined with the B lifetime we determine |V_cb| = 0.0406 +-0.0009(exp) +-0.0019(theory)

Le nouveau genotype wjr::(1629) de tournesol (helianthus annuus l. , seconde plante oleagineuse du monde) est remarquable par son caractere isomature : il possede deux ou plusieurs capitules symetriques qui fleurissent et murissent simultanement. Son interet sur le plan agronomique est prometteur. Il est mis en evidence que la realisation du caractere isomature est sous la dependance de un a trois genes dominants et d'un effet maternel. Ce resultat impliquera necessairement, dans le futur, l'utilisation d'un parent femelle isomature pour le creation d'hybrides commerciaux

Le rein du Mammifère est un organe essentiel dont le rôle est de maintenir l’homéostasie et de purifier le sang en éliminant les déchets issus du métabolisme. Le développement du rein définitif, débute par l’émergence du bourgeon urétéral (BU) au niveau de l’extrémité postérieure du canal néphrique (CN). Le BU subit ensuite un processus complexe d’arborisations stéréotypées aboutissant à la formation du système de canaux collecteurs (CC) et de l’uretère. A chaque nouvelle arborisation, l’invasion de l’épithélium induit la condensation du mésenchyme adjacent pour former des agrégats pré-tubulaires, précurseurs des unités de filtration du rein, les néphrons. Ainsi, les deux structures tubulaires épithéliales rénales que constituent les CCs et les néphrons se développent de façon coordonnée par des mécanismes différents finement régulés. Le facteur de transcription HNF1B joue un rôle essentiel dans la morphogenèse d’organes complexes tels, que le rein, le pancréas ou le foie. Chez l’Homme, les mutations hétérozygotes de HNF1B entraînent l’apparition du syndrome « Renal Cysts And Diabetes » (RCAD), caractérisé par un diabète précoce, une hypoplasie pancréatique ainsi que des défauts de morphogenèse des tubules rénaux et du tractus génital. Notre laboratoire a montré que HNF1B est requis durant le développement précoce du rein, pour l’émergence du BU et l’initiation de la néphrogenèse chez la souris. Hnf1b s’exprime aussi plus tardivement lors de la formation du néphron et dans l’ensemble des CCs, suggérant ainsi un rôle plus tardif et spécifique dans ces structures. Étant donné les interactions réciproques existant entre le mésenchyme métanéphrique et le BU, et pour discriminer les fonctions spécifiques de Hnf1b dans chacun de ces compartiments, nous avons inactivé ce gène dans ces deux populations de cellules grâce à une stratégie d’invalidation conditionnelle chez la Souris. L’invalidation conditionnelle de Hnf1b dans les progéniteurs des néphrons avec la lignée Wnt4-EGFPCre entraîne une létalité précoce des mutants associée à une hypoplasie rénale. Les mutants présentent une arborisation normale mais ne développent aucun néphron. Ce défaut est associé à une diminution de l’expression de composants de la voie Notch (Lfng, Dll1, Jag1) et des facteurs Irx1/2 qui sont respectivement des régulateurs potentiels de la spécification des segments proximal et intermédiaire. De plus, HNF1B est recruté in vivo au niveau des séquences régulatrices de ces gènes. La surexpression d’une forme dominant-négatif de HNF1B dans des embryons de Xénope provoque la diminution de l’expression de marqueurs spécifiques des segments proximal et intermédiaire du pronéphros montrant ainsi que la fonction de HNF1B semble conservée au cours de l’évolution des Vertébrés. L’inactivation de Hnf1b dans le CN et ses dérivés, avec la lignée HoxB7-Cre, entraîne de multiples anomalies urogénitales, en partie dues à une activité mosaïque de la Cre-recombinase. L’analyse de l’architecture des branches du BU montre que le nombre d’extrémités ainsi que leur longueur sont massivement réduits chez les mutants. En outre, la géométrie générale de l’organe apparaît désordonnée. En associant l’invalidation mosaïque de Hnf1b avec une lignée portant un rapporteur fluorescent membranaire EGFP ou Tomato selon que les cellules sont recombinantes ou non, nous avons pu suivre par imagerie en temps réel le comportement des cellules lors de l’arborisation du BU. Les cellules mutantes apparaissent exclues des extrémités des branches ce qui suggère que HNF1B pourrait y agir de façon autonome-cellulaire pour promouvoir l’arborisation. De plus, la polarité des cellules des CCs semble perdue chez les mutants et le système collecteur ne peut se différencier correctement. On observe alors l’apparition de dilatations, voire même de kystes, dans les CCs, à la fois in vivo et in vitro [...]
Mammalian kidney is an essential excretory organ that regulates fluid balance, osmolarity and pH. It also ensures blood filtration to excrete metabolism end products and drugs. The initiation of definitive mammalian kidney development is marked by the emergence of the ureteric bud (UB) from the Wolffian Duct (WD). The UB subsequently undergoes a complex and stereotyped process of branching to give rise to the entire urinary collecting duct (CD) system and the ureter. As the UB undergoes branching morphogenesis, the tip cells control multiple events including mesenchymal-to-epithelial conversion and subsequent formation of regionalized nephrons, the filtering units of the kidney. The POUhomeodomain transcription factor HNF1B plays a critical role in the early differentiation of various organs including pancreas, liver and kidney. In humans, HNF1B heterozygous mutations cause the complex syndrome known as Renal Cysts and Diabetes, characterized by kidney, genital tracts and pancreas abnormalities as well as early onset of Diabetes. Our lab has previously shown that HNF1B is involved in early mouse kidney development for UB timing outgrowth and branching, as well as for induction of nephrogenesis. However, Hnf1b is also expressed during branching in UB and CDs, and at every nephrogenesis steps, suggesting a later and specific role during both processes. Given the reciprocal interactions between the UB and the metanephric mesenchyme, to discriminate the specific Hnf1b functions in these compartments, we inactivated this gene individually in those two tissues, through the use of appropriate Cre-recombinase mouse lines. Hnf1b-specific inactivation in nephron progenitors, using the Wnt4-EGFPCre mouse line, leads to mutant newborns death soon after birth, with mild hypoplastic kidneys that lack all nephron segments but exhibit rather correct UB branching. Mutant renal vesicles develop and polarize normally but fail to progress to correctly patterned “S” shaped bodies (SSB). This is associated with strong downregulation of the Notch pathway components Lfng, Dll1 and Jag1 and the Irx1/2 factors, which are potential regulators of proximal and Henle’s loop segment fates. Moreover, HNF1B is recruited in vivo to the regulatory sequences of most of these genes. Overexpression of a HNF1B dominant-negative construct in Xenopus embryos causes downregulation specifically of proximal and intermediate pronephric segment markers. Our results show that HNF1B is required for the acquisition of a proximointermediate segment fate in vertebrates, thus uncovering a previously unappreciated function of a novel SSB subcompartment in global nephron segmentation and further differentiation. By removal of Hnf1b from the WD and the UB using the Hoxb7-Cre mouse line, we observe multiple urogenital tract abnormalities in part due to an early mosaic Hoxb7-Cre activity. Analyzing kidney tree architecture, we found that tips number and length are massively reduced and UB branching is severely miss-patterned in mutants. Combining the Hnf1b mosaic deletion with a reporter line expressing a membrane-associated fluorescent protein EGFP or Tomato, we developped an original genetic approach that allows visualize the behavior of recombined and WT cells within the UB branches. By time lapse on organotypic kidney cultures we observe, at different stages, that cells lacking Hnf1b become excluded from the UB tips. This suggests that HNF1B may be required cell autonomously at the tip domain for the branching process. Moreover, collecting duct cell polarity appears impaired in mutants and do not further maturate properly becoming either dilated or over cystic both in vivo and in vitro [...]

On retrouve dans les météorites primitives des grains qui se sont condensés dans différents environnements stellaires et sont restés intacts après la formation du système solaire. L'identification du site d'origine de ces grains pré-solaires est effectuée grâce à la comparaison entre les abondances isotopiques mesurées et celles prédites par les modèles stellaires. Nous présentons dans ce manuscrit les analyses de deux expériences effectuées à l'installation ALTO avec le spectromètre magnétique split-pole, visant à réduire les incertitudes associées à deux réactions jouant un rôle dans la production des isotopes utilisés pour identifier les grains de novæ. Ces derniers sont caractérisés par des abondances extrêmes en ¹³C, ¹⁵N et ³⁰Si, mais la découverte dans certains grains d'isotopes caractéristiques de la nucléosynthèse dans les supernovæ à effondrement de coeur (CCSN) a remis en question cette origine. La première étude concerne l'impact du taux de la réaction ¹³N(a,p)¹⁶O sur les abondances en ¹³C prédites par de récents modèles de CCSN. Nous procédons à une ré-évaluation du taux de cette réaction en utilisant une méthode Monte Carlo pour obtenir des incertitudes statistiques. Les largeurs partielles alpha des états du noyau composé ¹⁷F sont déterminées en se basant sur les propriétés des états analogues du noyau miroir ¹⁷O qui ont été mesurées en utilisant la réaction de transfert alpha ¹³C(7Li,t)¹⁷O. Nous nous intéressons ensuite à la réaction ³⁰P(p,g)³¹S, qui est une des dernières réactions dont l'incertitude du taux a un impact important sur les prédictions faites par les modèles de novæ classiques, notamment des abondances en ³⁰Si. Pour réduire les incertitudes sur les propriétés spectroscopiques du noyau composé ³¹S, une étude de la réaction ³¹P(³He,t)³¹S a été effectuée. Les tritons et les protons de décroissance venant des états peuplés du ³¹S ont été détectés simultanément à l'aide du spectromètre et de détecteurs silicium à pistes. L'étude des corrélations angulaires proton est présentée et les rapports de branchement extraits
Primitive meteorites contain several types of dust grains that condensed in different stellar environments and survived destruction in the early Solar System. The stellar sources where these presolar grains come from are identified through comparisons between measurements of isotopic abundances and predictions by stellar models. In this manuscript is presented a detailed analysis of two experiments performed at the ALTO facility, using the split-pole magnetic spectrometer, aiming at reducing the nuclear uncertainties associated to two reactions which rate uncertainty affects the synthesis of isotopes used to identify putative novae grains. These grains are characterised by extremely high ¹³C, ¹⁵N and ³⁰Si isotopic abundances, but isotopic signatures found in a few grains indicate also a possible core-collapse supernovae (CCSN) origin. We first study the impact of the ¹³N(a,p)¹⁶O reaction rate uncertainty on ¹³C abundances predicted by recent CCSN models. We perform a re-evaluation of this reaction rate using a Monte Carlo approach to obtain meaningful statistical uncertainties. Alpha partial widths of states in the ¹⁷F compound nucleus are determined using the spectroscopic informations of the analog states in the ¹⁷O mirror nucleus that were measured using the ¹³C(7Li,t)¹⁷O alpha-transfer reaction. We then study the ³⁰P(p,g)³¹S reaction, which is one of the few remaining reactions which rate uncertainty has a strong impact on classical novae model predictions, in particular for ³⁰Si abundances. To reduce the nuclear uncertainties associated to this reaction, we studied the ³¹P(³He,t)³¹S reaction. Triton and proton decays from the populated states in ³¹S were detected simultaneously using the spectrometer and silicon strip detectors. The study of the angular correlations of proton decays is presented and branching ratios are extracted

博士
國立成功大學
基礎醫學研究所
94
Branching tubulogenesis is an important feature of many organs during embryonic development. Madin-Darby canine kidney (MDCK) cells develop branching tubules in three-dimensional collagen gel in the induction of hepatocyte growth factor (HGF). Discoidin domain receptor I (DDR1) is a receptor tyrosine kinase and serves as the receptor for collagen in addition to integrins. MDCK cells normally express DDR1. However, the function of DDR1 in this in vitro model system has not been understood. To dissect the function of DDR1, we established stable-transfected MDCK cells that harbored DDR1a, DDR1b or dominant-negative DDR1, and cultured these transfectants in collagen gel with HGF to analyze for changes in branching morphogenesis. Tubulogenesis is a functional result of cell proliferation, migration, and cell survival. Overexpression of DDR1a or DDR1b inhibited the cell proliferation and collagen-induced cell migration, which in turn suppressed HGF-induced branching tubulogenesis. In contrast, dominant-negative DDR1 could enhance apoptosis and cell migration, which resulted in disruption of tubule structure and developing mostly cell aggregates with multiple long extended processes. Overexpression of DDR1a or 1b in MDCK cells decreased cell apoptosis on collagen gel, whereas dominant-negative DDR1 enhanced cell apoptosis, suggesting that the DDR1 functions in maintaining cell survival. Collagen-induced cell migration is mainly triggered by a2b1 integrin, whereas DDR1a and 1b may serve as a negative regulator for a2b1 integrin during migration. Here, we showed that DDR1 downregulated collagen-induced tyrosine phosphorylation of Signal transducers and activators of transcription (Stat) 1/3 and cell migration triggered by a2b1 integrin. Overexpression of DDR1 increased the binding DDR1a/b to Src-homology-2 (SH2)-domain-containing protein 2 (SHP-2) and upregulated the tyrosine phosphatase activity of SHP-2, which sequentially suppressed the activation of Stat1/3 and cell migration. We demonstrated that the tandem Src-homology-2 (SH2) and Phosphotyrosyl phosphatases (PTP) domains of SHP-2 were responsible for interaction with DDR1, and that both tyrosine phosphorylation sites 703 and 796 of DDR1 were essential for this interaction. Mutation of tyrosine 703 or 796 of DDR1 abolished the ability of DDR1 to inhibit the tyrosine phosphorylation of Stat1/3, restored collagen-induced cell migration and the HGF-induced branching tubulogenesis. These results indicate that SHP-2 mediates the DDR1-suppressed of Stat1/3 activation and cell migration, as well as the HGF-induced branching tubulogenesis in collagen gel.

We use a global fit to determine the form factor slopes and branching fractions of the decays B --> Dlnu and B --> D*lnu. We reconstruct Dl pairs and construct a 3-dimensional distribution binned in lepton momentum, D momentum and cosTheta(B-Dl). These kinematic variables provide good separation between the signal and background. We fit electron and muon samples separately and combine them after calculating systematic uncertainties. The form factor slopes, rhoD^2 for B --> Dlnu and rho^2 for B --> D*lnu decays, are measured to be rhoD^2 = 1.22 +- 0.04 +- 0.07 and rho^2 = 1.21 +- 0.02 +- 0.07, where the errors are statistical and systematic, respectively. Branching fractions are fitted to be B(B+ --> D0lnu) = (2.36 +- 0.03 +- 0.12) % and B(B^+ --> D*0lnu) = (5.37 +- 0.02 +- 0.21) %. We use these results to determine the products, G(1)|Vcb| = (43.8 +- 0.8 +- 2.3)*10^{-3} and F(1)|Vcb| = (35.7 +- 0.2 +- 1.2)*10^{-3} of the form factors at zero recoil and the CKM matrix element |Vcb|, from which |Vcb| can be extracted using theoretical input.

The thesis describes the study of the rare charged kaon decay K00 e4 on the NA62 experiment at CERN. This decay is interesting from the chiral perturbation theory point of view. In this work the data from 2007 recorded on NA62 ex- perimental setup were analyzed. The measurement of branching ratio for this process normalized to K00 3π decay has been performed. Also the form factor measurement has been done and the cusp singularity has been observed. 1

碩士
國立成功大學
統計學系
102
For de novo assembly of next-generation sequencing data, the selection of assembly tool and the corresponding parameters have a great effect on the quality. The tool is treated as the branching factor. Three tools: Velvet, SOAPdenovo and ABySS are considered which are regarded as the levels of the branching factor. And the parameters which are special for each tools are treated as nested factors. Besides, the parameters shared by all tools are regarded as shared factor. In this study, we want to choose the tool and corresponding parameters that optimize the quality under limited resource. Because the de novo assembly is simulated with computer, the selection becomes the optimization problem of computer experiment with respect to the factors. We propose a sequential procedure to choose the assembly tool and the corresponding optimal parameters simultaneously. Firstly, we apply the Branching Latin hypercube design to explore the response surface. Secondly, Gaussian Process model is applied to construct the response surface and select the next experiment point by maximizing the Expected Improvement function until the stopping criterion is meet. The performance of the numerical simulation seems well. The implementation of real data can search into the region with larger value of response quickly and access to a better experiment point compared to other methods.

碩士
國立成功大學
企業管理學系碩博士班
97
This paper uses secondary statistic data to discuss the macroeconomic factors that influence banks’ international strategy. The foreign exchange deposit and loan is set to be the dependent variable, and the macroeconomic statistics from other aspects the independent variables. The study includes the historical data from 1997 to 2008, with the panel data technique, to implement the multiple regression analysis to examine the relationship between the variables. The result of the study finds that there is variation in the operation model of oversea branches with the domestic branches, particularly in the entry modes, which shows differences with the previous studies. This study’s variables in the domestic aspects indicate significant influences in banks’ international strategy of domestic aspect.